Principal elements of English law
England's most authoritative law is statutory
legislation, which comprises
Acts of Parliament,
bye-laws. In the absence of any statutory law, the common law with its principle of
stare decisis forms the residual source of law, based on judicial decisions, custom, and usage.
Common law is made by sitting
judges who apply both
statutory law and established principles which are derived from the
Equity is the other historic source of judge-made law. Common law can be amended or repealed by
Not being a
civil law system, English law has no comprehensive
codification. However, most of its criminal law has been codified from its common law origins, in the interests both of certainty and of ease of prosecution.
 For the time being,
murder remains a common law crime rather than a statutory offence.
Although Scotland and Northern Ireland form part of the United Kingdom and share Westminster as a primary legislature, they have separate legal systems outside of English Law.
International treaties such as the
Treaty of Rome
 or the
have effect in English law only when adopted and ratified by Act of Parliament.
 Adopted treaties may be subsequently denounced by executive action.